I want to import some modules in my virtual environment like Flask, Pandas, Matplotlib etc. But the problem is that the terminal returns me the following issue:

(env) PS C:\Users\User\Desktop\Mehr\Python\Blockchain-Course> pip install matplotlib
WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/matplotlib/
WARNING: Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/matplotlib/
WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/matplotlib/
WARNING: Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/matplotlib/
WARNING: Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError("Can't connect to HTTPS URL because the SSL module is not available.")': /simple/matplotlib/
Could not fetch URL https://pypi.org/simple/matplotlib/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/matplotlib/ (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available.")) - skipping
ERROR: Could not find a version that satisfies the requirement matplotlib (from versions: none)
ERROR: No matching distribution found for matplotlib
WARNING: You are using pip version 21.2.3; however, version 21.3.1 is available.
You should consider upgrading via the 'C:\Users\User\Desktop\Mehr\Python\Blockchain-Course\env\Scripts\python.exe -m pip install --upgrade pip' command.

I've never had any problems with it and yesterday it worked perfectly, does someone knows what to do?

CodePudding user response：

The problem could have been caused by the DLLs in the C:\Windows\System32 folder (e.g. libcrypto-1_1-x64.dll or libssl-1_1-x64.dll or others) placed there by other software.

It may be fixed installing openSSL from https://slproweb.com/products/Win32OpenSSL.html which replaces the dlls by more recent versions.

CodePudding user response：

1. first install openssl, please refer to this page
2. install python and ./configure --with-openssl=/home/username/openssl at last
3. run python -m ssl and nothing outputs, it's ok.

You can refer to this page for more details.